Evaluation of tear production, intraocular pressure, retinography and ocular biometry in bovine Nelore and Gir breeds

The ophthalmological parameters were evaluated of 38 male Nelore bovine (n=19, GN group) and Gir (n=19, GG group), with 15 months age. The ophthalmological examinations by Schirmer 1 (TLS-1), aplanation tonometry, retinography and B-mode ultrasonography were done. The results of the TLS-1, aplanation tonometry and ocular biometry were evaluated by analysis of variance and means compared by the Tukey test. A descriptive analysis of the anatomical structures was performed for the retinography examination. TLS-1 and tonometry did not differ (P >= 0.05) in the comparisons between the eyes and between the groups. Retinography allowed the visualization of the optic disc, retinal vessels, tapetal and non-tapetal fundus, without any anatomical differences between the breed. In the ocular biometry, higher values were observed in Gir animals for measurements of axial length (CAx), lens thickness (EL) and depth of the vitreous chamber (CV), both horizontal (CAH) and vertical (CAV) imaging planes. Ophthalmologic examinations can be performed on the field without compromising animal welfare. Differences between Nelore and Gir bovines were identified only by B-mode ultrasonography.